Evidence suggests that maternal obesity increases the risk of fetal death, stillbirth, and infant death; however, the optimal body mass index ( BMI ) for prevention is not known.
Researchers have performed a systematic review and meta-analysis of cohort studies of maternal BMI and risk of fetal death, stillbirth, and infant death.
Thirty eight studies ( 44 publications ) with more than 10 147 fetal deaths, more than 16 274 stillbirths, more than 4311 perinatal deaths, 11 294 neonatal deaths, and 4983 infant deaths were included.
The summary RR per 5-unit increase in maternal BMI for fetal death was 1.21 ( I2 = 77.6%; n = 7 studies ); for stillbirth, 1.24 ( I2 = 80%; n = 18 studies ); for perinatal death, 1.16 ( I2 = 93.7%; n = 11 studies ); for neonatal death, 1.15 ( I2 = 78.5%; n = 12 studies ); and for infant death, 1.18 ( I2 = 79%; n = 4 studies ).
The test for nonlinearity was significant in all analyses but was most pronounced for fetal death.
For women with a BMI of 20 ( reference standard for all outcomes ), 25, and 30, absolute risks per 10 000 pregnancies for fetal death were 76, 82 and 102; for stillbirth, 40, 48 and 59; for perinatal death, 66, 73 and 86; for neonatal death, 20, 21 and 24; and for infant death, 33, 37 and 43, respectively.
In conclusion, even modest increases in maternal BMI were associated with increased risk of fetal death, stillbirth, and neonatal, perinatal, and infant death.
Weight management guidelines for women who plan pregnancies should take these findings into consideration to reduce the burden of fetal death, stillbirth, and infant death. ( Xagena )
Aune D et al, JAMA 2014;311:1536-1546